I ran across this manual focus Vivitar and i bought it today for $80 dollars, i said to myself "what the heck" i got nothing to loose. I sure didn't loose anything, I am completely blown away by the high quality of this thing, it is AMAZING and it is Macro also. Basically it looks like it has the same excellent glass as the $589 dollar Nikon. This lens does take more light than the 70-300, the example bellow are set around f5 and at 200mm. The First photo is from the Vivitar and i am not sure why it doesn't say f5.5 and 20mm but both these photos were set up the same. If i put the Vivitar at 2.8 it gets a ton more light than the Nikon. It is Incredible what you can find out there.